Polymer Molds and Tools for the Plastic Industry Produced by Addictive Manufacturing

Polymer additive manufacturing is booming in a number of sectors, including the automotive, medical and aerospace industries.

Polymer additive manufacturing has established itself as an essential means of producing prototypes and mock-ups. By printing a prototype, a part can be tested before the more expensive metal tooling is used for mass production.

Polymer additive manufacturing, on the other hand, remains a delicate process for mass production. Although many counter-examples exist, polymer additive manufacturing cannot achieve production rates competitive with plastic injection molding, and production runs of over 1,000 parts are rare.

Moreover, in some areas, parts obtained by additive manufacturing do not meet customer requirements: mechanical performance and durability are not equivalent to those of an injected part, the surface finish does not allow the same metallization techniques to be used, and the material grades are different from those used in injection molding. The transition from plastic injection molding to additive manufacturing remains a challenge for the plastics processing industry: it is necessary to requalify a material and readapt a design in order to adapt to the constraints of the process.

However, additive polymer manufacturing can also bring flexibility and agility to conventional plastics processes (injection, thermoforming, extrusion): it is possible to print complex geometries and their thermal regulation channels (injection molds, conformers or thermoforming molds) in a very short time and at a controlled price: an injection tool up to 300 cm ³ can be produced in less than 24 hours. While conventional metal toolmaking requires several stages (machining, wire cutting, EDM, texturing), additive polymer manufacturing reduces the number of stages, making polymer toolmaking more responsive. On the other hand, the tooling produced has a limited lifespan compared with conventional metal tooling, particularly when abrasive materials are used, and lower productivity: as the polymer is insulating, the heat transfer between plastic material and tooling will be lower, and the time required to cool the plastic is consequently longer. Today, polymer additive manufacturing mold inserts are therefore not suitable for mass production (runs of over 5,000 parts).

In this article, the various polymer material/additive manufacturing technology combinations available for tooling applications are briefly presented. This is followed by a description of concrete use cases in injection, thermoforming and extrusion, to give an overview of the technology and its benefits for plastics processing. These examples are followed by a techno-economic...